Shares in Sportingbet, the world's largest online gambling operator, fell sharply last Thursday after the company warned that a rise in US costs and unfavourable currency fluctuations would put a dent in its second half financial results. 'Sportingbet has recently seen an increase in the cost of processing customer funds and this together with the adverse dollar/sterling currency movement during this year will have an impact on the second half of the financial year,' said Peter Dicks, Sportingbet chairman.

The company also announced that losses before tax for the six months to September 30 widened to £3.8 million ($5.91 million) from £1.6 million ($2.48 million) the year before.

However, the UK-based company said its European operations remained on track to reach profitability before the end of the year and reported a 41% rise in turnover to £494.5m ($770.13m) for the six months to September 30, as customer numbers rose 35% to 752,706 despite being Sportingbet's quiet season.

57% of new customers were acquired by Sportingbet through marketing, while the rest of the company’s new customers came from Sportingbet’s acquisition of rival Sporting Odds in July and a deal with Austria's Sportswetten.

The company, which launched in the US with the acquisition of Sportsbook last year, said it expected further consolidation in the industry, as smaller companies were bought or ceased trading.

The company warned that the regulatory environment in the US remained unclear, but added that there was little support in the US Senate for a bill seeking to ban online gambling.